VARIATIONS IN THE ACIDITY OF THE URINE. 25P 
The results obtained on these seven days correspond 
closely with the foregoing, but they are exhibited in a 
less exaggerated degree. On the first and sixth days the 
urine after breakfast maintained its acidity, though on the 
first it was greatly reduced. On the sixth day the effect 
of both breakfast and dinner was comparatively small. 
On all the other days the urine became alkaline after both 
meals. The succession of events after each meal was quite 
uniform throughout. In an hour or two the acidity of the 
- urine began to decline, and it sank to a minimum or 
changed to alkalinity at the second, third, or fourth hours ; 
then, beginning to recover, the acidity gradually increased 
in degree until it attained its ordinary level. No depar- 
ture from this sequence of events occurred, even as an 
exception. 
What may be the circumstances which cause the very 
considerable inequalities between the several days, and 
between this set of observations and the preceding, — 
why a meal one day should only produce a slight depres- 
sion of the acidity, another day render the urine neutral 
or faintly alkaline, and a third day change it for several 
hours to a strongly alkaline reaction, — is not capable of 
complete answer. But several of the disturbing causes 
have revealed themselves in the course of these observa- 
tions, and will be discussed later on. 
The effect of mixed food was further ascertained on 
four additional days, on which the times of emission of 
the urine were so irregular that the day tables could not 
be collected into one table of averages. On three of 
these, instead of being confined to two meals a day, the 
subject of experiment partook of four meals, which was 
according to his customary habit of life; and at dinner 
and supper he was allowed a pint of ale. 
VOL, XV. LL 
